This invention relates to steel rule die cutting and more particularly to an improved multi-cavity die with movable and adjustable cutting units.
Steel rule dies are commonly used for cutting cloth and cloth-like substances such as natural textiles and synthetic materials like vinyl. Steel rule dies are particularly advantageous in the repetitive cutting of a specific shape for use in clothing, furniture, shoes, and automotive trim panels. In brief, a steel rule cutting die typically comprises a base substrate or backing board in which grooves are cut and lengths of sharpened blade, known as steel rule, is formed to the same shape as the grooves and inserted in the grooves. The grooves are cut in the substrate in the pattern that is desired to be cut out of the material. Thus, when the steel rule is placed into the grooves, it forms cutting edges in the shape of the desired patterns. This die can be used together with a cutting press so that the die is pressed against a stack of material and the material is cut. Multiple layers of material can be cut with one pressing operation. Typically, one die will include several cavities, each with a different pattern and defined by a closed length of rule, so that several multiple patterns can be cut during a single pass through the press. Multiple cavities on a single die are nested together in an efficient configuration to minimize scrap material.
One problem with typical steel rule dies is the removal of scrap material from the regions between the cavities, i.e., between sections of adjacent rule, after each cutting process. Due to the bevel on the steel rule, scrap material that is situated between two cavities becomes compressed between the cavities and is difficult to remove. An operator must, therefore, perform a time-consuming cleaning of the die between each cutting process. Where the dies are closely spaced, the cleaning process is especially difficult. This results in extra cost and a decrease in the throughput of the cutting process. In order to alleviate the problem of cleaning scrap material, most dies have their cavities spaced apart from one another by at least 1/4. This spacing of 1/4 inch can cause significant cost in terms of scrap material.
Another problem is that, once the groove is cut into the substrate and the steel rule is placed into the groove, the cavities are permanently arranged in the die. If the pattern of one cavity needs to be modified in any respect, it is necessary to construct a completely new die at significant expense. In other words, there is no flexibility to change the patterns being without performing the costly and time consuming procedure of making a whole new die.